Ask HN: Founders who offer free/OS and paid SaaS, how do you manage your code?

I am curious as to how do you solve the problem of maintaining different offerings of your product.

1) Do you have two separate codebases for free and paid? Or do you have some sort of standard workflow where you have two different branches? 2) How do you handle updates to your product? 3) How about employee access?

Thanks in advance!